var Base64 = {
	_keyStr : "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="
}

Base64.encode = function(input) {
	var output = "";
	var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
	var i = 0;
	input = Base64._utf8_encode(input);
	while(i < input.length) {
		chr1 = input.charCodeAt(i++);
		chr2 = input.charCodeAt(i++);
		chr3 = input.charCodeAt(i++);
		enc1 = chr1 >> 2;
		enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
		enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
		enc4 = chr3 & 63;
		if(isNaN(chr2)) {
			enc3 = enc4 = 64;
		} else if(isNaN(chr3)) {
			enc4 = 64;
		}
		output = output +
			Base64._keyStr.charAt(enc1) + Base64._keyStr.charAt(enc2) +
			Base64._keyStr.charAt(enc3) + Base64._keyStr.charAt(enc4);
	}
	return output;
}

Base64.decode = function(input) {
	var output = "";
	var chr1, chr2, chr3;
	var enc1, enc2, enc3, enc4;
	var i = 0;
	input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
	while(i < input.length) {
		enc1 = Base64._keyStr.indexOf(input.charAt(i++));
		enc2 = Base64._keyStr.indexOf(input.charAt(i++));
		enc3 = Base64._keyStr.indexOf(input.charAt(i++));
		enc4 = Base64._keyStr.indexOf(input.charAt(i++));
		chr1 = (enc1 << 2) | (enc2 >> 4);
		chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
		chr3 = ((enc3 & 3) << 6) | enc4;
		output = output + String.fromCharCode(chr1);
		if(enc3 != 64) {
			output = output + String.fromCharCode(chr2);
		}
		if(enc4 != 64) {
			output = output + String.fromCharCode(chr3);
		}
	}
	output = Base64._utf8_decode(output);
	return output;
}

Base64._utf8_encode = function(string) {
	string = string.replace(/\r\n/g, "\n");
	var utftext = "";
	for(var n = 0; n < string.length; n++) {
		var c = string.charCodeAt(n);
		if(c < 128) {
			utftext += String.fromCharCode(c);
		} else if((c > 127) && (c < 2048)) {
			utftext += String.fromCharCode((c >> 6) | 192);
			utftext += String.fromCharCode((c & 63) | 128);
		} else {
			utftext += String.fromCharCode((c >> 12) | 224);
			utftext += String.fromCharCode(((c >> 6) & 63) | 128);
			utftext += String.fromCharCode((c & 63) | 128);
		}

	}
	return utftext;
};

Base64._utf8_decode = function(utftext) {
	var string = "";
	var i = 0;
	var c = c1 = c2 = 0;
	while(i < utftext.length) {
		c = utftext.charCodeAt(i);
		if(c < 128) {
			string += String.fromCharCode(c);
			i++;
		} else if((c > 191) && (c < 224)) {
			c2 = utftext.charCodeAt(i + 1);
			string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
			i += 2;
		} else {
			c2 = utftext.charCodeAt(i + 1);
			c3 = utftext.charCodeAt(i + 2);
			string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
			i += 3;
		}
	}
	return string;
}

module.exports = {
	Base64
}
// module.exports = {
// 	encode:Base64.encode,
// 	decode:Base64.decode,
// }